Pressure translating apparatus and process

ABSTRACT

An apparatus and process for conversion of thermal energy into mechanical energy wherein the working fluid of a heat engine is in contact with one side of a pressure sensitive means such as a piston or diaphragm, the other side of the pressure sensitive means being in contact with an incompressible fluid which in turn is in contact with the first ends of a pair of opposing pistons, the pistons being linked by mechanical linkage, the second end of one piston being in contact with a fluid to be pumped and the second end of the second piston being in contact with a cushion chamber, providing a quiet running thermal engine without dynamically unbalanced forces, with substantially reduced influence on the performance and smooth running of the dynamic instability inherent to free-piston systems generally, and with a positive control of the piston travel. The apparatus is particularly advantageously used in connection with a refrigeration system wherein the backside of the second end of each piston is in contact with the refrigeration fluid at evaporator pressure and the face of the second end of each piston is in contact with the refrigeration fluid at condenser pressure.

United States Patent 1 Wurm [ Jan. 9, 1973 [54] PRESSURE TRANSLATING APPARATUS AND PROCESS [76] Inventor: Jaroslav Wurm, 2240 S. 59th Avenue, Cicero, Ill. 60650 [22] Filed: June 28, 1971 [21] Appl. No.: 157,456

[52] US. Cl. ..62/116, 62/498, 417/383 [51] Int. Cl ..F25b 1/00 [58] Field of Search ..62/116, 498, 501; 417/383 Primary ExaminerWilliam F. ODea Assistant Examiner-P. D. Ferguson Attorney-Richard E. Alexander et al.

couoeus ev [57] ABSTRACT An apparatus and process for conversion of thermal energy into mechanical energy wherein the working fluid of a heat engine is in contact with one side of a pressure sensitive means such as a piston or diaphragm, the other side of the pressure sensitive means being in'contact with an incompressible fluid which in turn is in contact with the first ends of a pair of opposing pistons, the pistons being linked by mechanical linkage, the second end of one piston being in contact with a fluid to be pumped and the second end of the second piston being in contact with a cushion chamber, providing a quiet running thermal engine without dynamically unbalanced forces, with substantially reduced influence on the performance and smooth running of the dynamic instability in herent to free-piston systems generally, and with a positive control of the piston travel. The apparatus is particularly advantageously used in connection with a refrigeration system wherein the backside of the second end of each piston is in contact with the refrigeration fluid at evaporator pressure and the face of the second end of each piston is in contact with the refrigeration fluid at condenser pressure.

8 Claims, 4 Drawing Figures 3 65 PEVAPORATOR Poouoeusen.

HEAT

OUT

PATENTEDJAN' 9191:

FIG. 2

evuoxmoa HEAT Pcouoeusa 3 75 IDEAL POWER CYCLE APPROXIMATION OF REAL POWER CYCLE m n O c P P evcp.

COMPR%SSION CY C LE POWER CYCLE T JVII.

FREON' 22 Pressure ps i a GENERATOR AND COMPRESSOR VOLUMES We INIVENTOR:

JAROSLAV WURM ATT'YS PRESSURE TRANSLATING APPARATUS AND PROCESS Heretofore, heat actuated regenerative compressors have been used to power refrigerating systems as described in US. Pat. Nos. 3,474,641 and 3,491,554.

Other types of external combustion thermal engines have been well known in the art for many years to function as prime movers and to provide for conversion of thermal energy into mechanical energy. Heat actuated regenerative compressor-cooling systems wherein the refrigerant is also a working fluid of such compressor using carbon dioxide and sulfur dioxide have been described in US. Pat. No. 3,400,555. Internal combustion thermal engines used to power refrigeration systems have been described in US. Pat. applications, Ser. No. 91,833, Internal Combustion Heat Engine and Process, and Ser. No. 91,355, Internal Combustion Heat Engine and Process, both filed Nov. 23, 1970.

In the operation of the thermal engine for purposes such as air conditioning, it is highly desirable that the engine and associated apparatus be as quiet and vibration free as possible.

Therefore, it is an object of my invention to provide an improved pressure translating apparatus having dynamic balanced forces.

It is another object of my invention to provide an improved pressure translating apparatus affording positive piston motion.

It is another object of my invention to provide an improved pressure translating apparatus with reduced dynamic instability of the free-piston motion by means of the additional damping effect of the acceleratingdecelerating mass of an incompressible fluid.

It is still another object of my invention to provide an improved pressure translating apparatus wherein the operating pressure of the associated apparatus driven by such translating means may be different from the pressure of the thermal engine driving the pressure translating apparatus.

It is afurther object of my invention to provide an improved, quiet and trouble-free cooling system powered by a thermal engine coupled to the improved pressure translating apparatus which is assisted by the pressure of the refrigerant, in a separate refrigeration system.

These and other important objects will become apparent from the following description taken in conjunction with-the drawings showing preferred embodiments wherein:

FIG. 1 is a cross section view of one embodiment ofa thermal engine having a pressure sensitive means useful in conjunction with the pressure translating apparatus of this invention; I

FIG. 2 is a cross section view of the pressure translating apparatus of this invention in conjunction with a cooling system;

FIG. 2a shows enlargement of the flywheel interconnecting system of the apparatus shown in FIG. 2; and

FIG. 3 graphically illustrates the pressure volume relationship of the power cycle and the compression cycle using an apparatus according to this invention.

Referring specifically to FIG. 1, the heat-actuated regenerative compressor 1 comprises outer shell casing 2, insulation 4, and inner shell casing 5 defining gas chamber 6, which is generally cylindrical in shape.

toward the center of the chamber 6 to hub 18 extending substantia1ly the entire length of the chamber 6 separating cold section 19 from hot section 21 are cooling means 22, heat regenerative means 23, and heating means 24. The sizes of such heat transfer components shown in FIG. 1 are based upon current heat transfer materials, designs and techniques. However, it would be apparent to one skilled in the art that if more efficient heat transfer units become available, the size, proportionsand shapes of the heat transfer units could readily be changed accordingly. The large hub 18 and insulator 25 provide a long travel distance insulating cold section :19 from hot section 21 at the heat exchangers.' However, insulator '25 is not essential for all operating conditions.

Briefly, operation of the compressor is achieved by vane 20 moving gasfrom cold section 19 in order through the cooler-regenerator-heater into hot section 21 at an average higher temperature-pressure relationship and then returning the gas from hot section 21 in order back through the heater-regenerator-cooler to cold section 19 at an average lower temperature-pressure relationship. Vane frequencies of from about 15 to 500 cycles per minute are suitable for the operation of such a compressor, preferred frequencies being from about to 300 cycles per minute.

The heat actuated compressor is operated by use of gases having high thermal-conductivity and specific heat ratio. Preferred gases include hydrogen and monatomic inert gases such as helium. Either a single gas or mixtures of different gases may be used. Helium is especially preferred. The heat actuated regenerative compressor is described in more detail in US. Pat. Nos. 3,474,641 and 3,491,554.

Any power unit affording cycles of high and'low pressures is suitable for use in conjunction with the im-, proved pressure translating apparatus of this invention. Especially suitable power means include external combustion heat enginesas described above and internal combustion heat engines as described in U. S. Patent application Ser. Nos. 91,355 and 91,833 referred to above.

The pressure translating device of my invention receives its energy through a pressure responsive means in contact with the active volume ofthe heat engine. FIG. 1 shows pressure sensitive means 10 in contact with the active volume of the heat engine. Pressure sensitive means 10 comprises piston 32 adapted for reciprocating motion within cylinder 31 and having face 33 in communication with cold section 19 of said heat actuated regenerative compressor and face 34 in communication with the incompressible fluid in the pressure translating apparatus. Piston 32 reciprocates with substantially gas-tight relationship between cylinder 31 and cold section 19 maintained by bellows 35, attached to one end of inner shell casing and at the other end to piston 32.

Bellows 35 must be constructed of suitable material and of suitable design to' permit the required flexing and expansion :while at the same time maintaining gas tight relationship between cold section 19 and the incompressible fluid in the pressure translating apparatus. Metal bellows are most satisfactory using copper, nickel and various stainless steel alloys or mixtures of copper and nickel; It is also apparent that other flexible materials such .as certain rubber or synthetic materialssuchas butyl rubber, a laminated structure embodying saran, and Dacron fabric impregnated with polymeric elastomer-may be used if they do not permit diffusion of the gases or liquids used. Suitable bellows are available commercially.

FIG. 2 shows the pressure translating apparatus of my invention in cross section with another embodiment of the pressure sensitive means-in communication with cold section 19 of heat actuated regenerative compressor 1. Diaphragm 36 issupported by diaphragm support block 37. The diaphragm may be of any suitable impermeable material such as stainless steel or plastic such as Dacron fabric impregnated with polymeric elastomer. Diaphragm 36 is in direct communication with cold portion 19 of heat engine 1 on one side and in direct communication with fluid 39 on the opposite.

side. Diaphragm support block 37 is mounted in exterior fluid tight relationshipto cylinder 31 and fluid vessel 38, but ininternal communication with cold section 19 of heat actuated regenerative compressor 1 and an incompressible fluid 39 such as oil. Any'incompressible fluid is satisfactory for use in the pressure translating apparatus ofmy invention. Particularly preferred is.an oil having lubricating properties. Fluid vessel 38 is attached in external fluid tight relationship to cylinder 40,, but in internalcommunication with pistons 43 and 46. Cylinder 40 defines compression chamber 41 at one end and cushion chamber 42 at the opposite end. Compression piston 43 has one end 44 in contact with the above described incompressiblefluid and the oppositevend 45 in contact with compression chamber, 41.

Cushion piston 46 has one end 47 in contact with the above described incompressible. fluid and the opposite end 48 in contact, with cushion chamber 42. Compression piston 43 has seal 60 near end 45 and seal 6 1 near end, 44. Cushion piston 46 has seal 63 near end 48 and seal 62 near end 47. These seals may be of any suitable material permitting free movement of the pistons within the cylinder while maintaining fluid separation.

' For hermeticallysealed units, when lubricating oil is used as fluid 39, it is feasible, by methods known in the art, to have returns to fluid vessel 38 for oil which may have found its way into chambers 41 and '42. Compression piston 43 and compression chamber 41 have the configuration of a Uniflow compressor. Piston 43 has one-way valves 58 through its face for communication with compression chamber 41 on both sides of end 45 of compression piston 43. Compression chamber 41 has end65, with one-way valves 59 for communication between compression chamber 41 and condenser 70 of a cooling system. Valves 58 and 59 operate solely by pressure differential in the same manner as in well known Uniflow compressors.

The piston interconnecting system is shown in FIG. 1

with piston 43 and piston 46 near their closest position of their cycle representing near the lowest pressure in the heat engine cycle. FIG. 2a is an enlarged portion of the piston interconnecting system showing pistons 43 and 46in the extreme separated portion of their cycle representing the highest pressure in the heat engine cycle. Reference to FIG. 2a is made to describe the piston interconnecting system. The pistons may be interconnected by any suitable mechanical linkage. providing simultaneous opposite movement of the pistons. Any internal rotably mounted member on ashafthaving rotably mounted connecting links attached at one end .to the member at to each other, one link rotably and the other link rotably attached to the cushion piston on the other end is suitable. A preferred internal linkage is shown in FIG. 2a wherein internal wheel 50 of the same apparatus as shown in section in FIG. 2 oscillates on shaft 51. Connecting rod. 53 is rotatably attached to wheel 50 by pin 52 at one end and at the other end rotatably attached by pin 54 to piston 43. Likewise, connecting rod- 56 is rotatably connected at one end to' wheel 50 by pin 57 and at the other end rotatably connected to piston 46 by pin 55. The interconnecting mechanical linkage through oscillating wheel 50 thus provides positive simultaneous opposite movement of pistons 43 and 46. The wheel may be connected in saddle fashion by pins 54 and 55 going through the piston and having identical linkages corresponding to 53 and 56 on the opposite side and connected to the wheel on the opposite side, or the wheel and pistons may be connected on one side as shown in FIG. 2a. The oscillating wheel connecting apparatus is completely within cylinder 40 affording hermetically sealed operation. 1 As shown in FIG. 2 the membrane 36 is in the position obtained by the minimum pressure condition of the heat engine. In this position pistons 43 and 46 are at their closest positionto each other. As rnembrane 36 is forced downward by increasing pressure in the beatengine, incompressible fluid 39 is likewise. forced downward and applies a greater pressure, to face 44 of piston 43 and face 47 of piston 46. ,The pistons are then forced away from each other, piston 43 compressing the refrigerant in chamber 4 1."

The apparatus of myinvention may be used to convert thermal energy into mechanical energy which may be' used, for instance, as a pump. As specifically illustrated in'FIG. 2 the pressure translating apparatus of my invention may be utilized as a pump to obtain the condenser pressure in any standard compression-condensation-expansion-evaporation cooling cycle. In

FIG. 2 piston 43 compresses the refrigerant in chamber" reducing the pressure to evaporation pressure, and through evaporator 72wherein heat is taken up from the exterior confined atmosphere. Theheat so taken up represents the, cooling of confined room airin the case of room air conditioning. The refrigerant flows from evaporator 72 to the portion of chamber. 41 behind piston 43. As piston 43 returns from the compressionstroke the refrigerant flows through valves 58 in piston 43 to the compression portion of chamber 41. The piston then moves in the compression stroke, valves 58 in piston 43 being closed, and the refrigerant is com- .pressed to condenser pressure flowing through valves 59 to the condenser. Valves 59 close while piston 43 returns from the compression stroke. During the cycle of compression piston 43, cushion piston 46 is operating against constant pressures in cushion chamber 42. As shown in FIG. 2, conduit 74 places the portion of chamber 42 behind piston 46 in contact with the evaporator of the cooling system and conduit 76 places the portion of chamber 42 ahead of piston 46 in contact with the condenser of the cooling system wherein the refrigerant is compressed by piston 43. Thus chamber 42 acts as a cushion chamber balancing the pressure forces of the compression portion of my apparatus. The pressure translation apparatus of my invention together with a suitable heat engine and standard air conditioning equipment provides a quiet vibration-free apparatus suitable for hermetically sealed operation.

The pressuretranslating apparatus of my invention provides for differing pressure ratios of the working gas of the heat engine and the refrigerant in the cooling cycle. Suitable differences in such pressure ratios may readily be obtained by varying the sizes of the opposite ends of each piston 43 and 46. Thus, the apparatus of my invention provides a suitable pressure translating apparatus where the pressure ratio in heat actuated regenerative compressors is from about 1.3 to 1.8 while the pressure ratio in desired cooling cycles is from 3.0 to about 45.

Referring to FIG. 3, the pressure-volume relation ships of the apparatus shown in FIGS. 1 and 2 are shown using helium as the working gas of the power unit and Freon 22 as the refrigerant in the cooling unit. This visone preferred combination of gases suitable. The points A on the refrigerant compression cycle and A on the power cycle correspond to the position of the translating apparatus shown in FIG. 2, while points C and C correspond to the position shown in FIG. 2a. It

is also seen from FIG. 3 that the power cycle of the heat engine is not modified by the pressure translating apparatus of my invention in an ideal case with the moving masses equal to zero. v

The apparatus of my invention may be used inassociation with conventional cooling systems. Refrigerants suitable for use in the cooling apparatus of my invention include those refrigerants suitable for compression-refrigeration cycles. Preferred refrigerants include halogenated hydrocarbons and S0,. Particularly preferred refrigerants are those selected from the group consisting of Freon l2 Freon 22. Freon designates a group of halogenated hydrocarbons containing one or more fluorine atoms which are widely used as refrigerants. The operating conditions and particular refrigerant used determine the pressure and temperature relationships of the closed refrigerating cycle. Under most operating conditions the evaporating temperature is from about 35 to 50 F. and the condensing temperature from about 90 to 150 F., both under constant pressure. Particularly preferred condensing temperatures are from about 105 to 140 F. In conventional air-conditioning systems the pressure ratio, defined as the ratio of the absolute pressure in the condenser and the absolute pressure in theevaporator, is from about 3 to 4%.

My invention relates to a cooling apparatus comprising a heat engine having pressure sensitive means of varying displacement in accordance with the working fluid of the heat engine having alternate cycles of higher and lower pressures and cooling apparatus comprising compression means, condenser means, expansion means, evaporation means and a contained refrigerant, wherein the improvement comprises the compression means having a cylinder defining a compression chamber at one end, a cushion chamber at the other end and a central portion in communication with the pressure sensitive means of the heat engine, opposing reciprocating compression and cushion pistons, each having a larger end reciprocating inthe compression chamber and the cushion chamber, respectively, and a smaller end reciprocating in the central portion of the cylinder, the larger end of the compression piston having one way valves therethrough in communication with the compression chamber on both sides of the larger end of the compression. piston, the compression chamber having the end nearest the larger end of the compression chamber when fully moved into the compression chamber with one way valves in communication with the portion of the compression chamber between the piston and that end and the pressurized output, the combination of the compression piston and the compression chamber forming a Uniflow type pump, the compression and cushion pistons being interconnected by mechanical interconnecting means providing positive opposite reciprocation of the pistons, and a fluid vessel containing an incompressible fluid in fluid-tight relationship and in internal communication with the pressure sensitive means on one end and the smaller-ends of the opposing pistons on the other end. Thus, the fluid is in direct communication with the pressure sensitive means and the smaller ends of the pistons and forces the pistons to reciprocate by the pressure of the fluid obtained by the varying displacement of the pressure sensitive means in response to the working fluid of the heat engine. In a preferred cooling apparatus, according to this invention, the evaporator of the cooling system is in communication with the backside of the larger end of both the compression and cushion pistons, thereby applying the evaporator pressure to the backsides of the pistons,and

the condenser of the cooling system is in communication with the forward side .of the larger end of the cushion piston thereby applying the condenser pressure to the forward side of the piston. Such an air cooling apparatus provides statically and dynamically balanced forces and is suitable for use as a residential or commercial air conditioning unit.

In the process for cooling contained exterior atmosphere by compression, condensation, expansion, evaporation cooling cycle, my invention is the improvement comprising the steps of compressing contained gaseous refrigerant by a reciprocating compression piston driven by an incompressible fluid in communication with the pressure sensitive means of a heat engine having alternate cycles of higher and lower pressure conditions, the compression piston being in interconnecting mechanical linkage with an opposing cushion piston so .that the pistons move oppositely to provide dynamic and pressure force balance, and damp the dynamic instabilities of the system. In a preferred process the evaporator of the cooling system is in communication with the backside of thelarger end of the compression piston and the cushion piston thereby applyingevaporator pressure to the backsides of both pistons and the condenser of the cooling system is in communication with the forward side of the larger end of the cushion piston thereby applying the condenser pressure to the forward side.

v While in the foregoing specification this invention has been described in relation to certain preferred embodiments thereof, and many details have been set forth for purpose of illustration, it will be apparent to those skilled in the art that the invention is susceptible to additional embodiments and that certain of the details described herein can be varied considerably without departing from the basic principles of the invention.

' I claim:

1. In a cooling apparatus comprising a heat engine having pressure sensitive means of varying displacement in accordance with the working fluid of the heat engine having alternate cycles of higher and lower pressures and cooling apparatus comprising compression means, condenser means, expansion means, evaporation means and a contained refrigerant, the improvement comprising; said compression means having a cylinder defininga compression chamber at one end, a cushion chamber at the other end and a central portion in'communication with said pressure sensitive means, opposing reciprocating compression and cushion pistons each having a larger end reciprocating in said compression chamber and said cushion chamber,

respectively and a smaller end reciprocating in the central portion of said cylinder, said larger end of said compression piston having one way valves therethrough in communication with said compression chamber on both sides of said larger end of the compression piston,-said .compression chamber having an end nearest said larger end of the compression piston when fully moved into said compression chamber with one, way valves in communication with the portion of said compression chamber between said piston and said end and the pressurized output, said pistons being interconnected by mechanical interconnecting means providing positive opposite reciprocation of said pistons, and a fluid vessel containing an incompressible fluid in fluid-tightrelationship and in internal communication with said pressure sensitive means on one end and said smaller ends of said opposing pistons on the other end, whereby said fluid being in direct communication with said pressure sensitive means and said smaller ends of said pistons force said pistons to rotatably fastened to said compression piston on the.

other end, and a second connecting link rotably mounted to' said member at from the fasteningbof said first connecting link and the other end rota fastened to said cushion piston.

3. The apparatus of claim -1 wherein said rotably mounted member is wheel-shaped and said connecting links are fastened at the rim thereof.

4. The apparatus of claim 1 wherein said fluid is lubricating oil and said refrigerant is Freon.

5. The apparatus of claim 1 wherein said evaporator means is in communication with thebackside of the larger end of said compression piston and said cushion piston thereby applying the evaporator pressure to said backsides and said condenser means is in communication with the forward side of the larger end of said cushion piston thereby applying the condenser pressure to said forward side.

6-. In a process for cooling contained exterior atmosphere by compression, condensation, expansion, evaporation cooling cycle, the improvement comprising; the steps of compressing contained gaseous refrigerant by a reciprocating compression piston driven by an incompressible fluid in communication with the pressure sensitive means of a heat engine having alternate cycles of higher and lower' pressure conditions, said conipressionpis'ton being in interconnecting mechanical linkage with an opposing cushion piston so that the pistonsmove oppositely to provide dynamic and pressure force balance, and damp the dynamic in- 

1. In a cooling apparatus comprising a heat engine having pressure sensitive means of varying displacement in accordance with the working fluid of the heat engine having alternate cycles of higher and lower pressures and cooling apparatus comprising compression means, condenser means, expansion means, evaporation means and a contained refrigerant, the improvement comprising; said compression means having a cylinder defining a compression chamber at one end, a cushion chamber at the other end and a central portion in communication with said pressure sensitive means, opposing reciprocating compression and cushion pistons each having a larger end reciprocating in said compression chamber and said cushion chamber respectively and a smaller end reciprocating in the central portion of said cylinder, said larger end of said compression piston having one way valves therethrough in communication with said compression chamber on both sides of said larger end of the compression piSton, said compression chamber having an end nearest said larger end of the compression piston when fully moved into said compression chamber with one way valves in communication with the portion of said compression chamber between said piston and said end and the pressurized output, said pistons being interconnected by mechanical interconnecting means providing positive opposite reciprocation of said pistons, and a fluid vessel containing an incompressible fluid in fluid-tight relationship and in internal communication with said pressure sensitive means on one end and said smaller ends of said opposing pistons on the other end, whereby said fluid being in direct communication with said pressure sensitive means and said smaller ends of said pistons force said pistons to reciprocate by the pressure of said fluid obtained by the varying displacement of the pressure sensitive means in response to the working fluid of said heat engine.
 2. The apparatus of claim 1 wherein said interconnecting means comprises, an internal rotably mounted member on a shaft within said cylinder, a first connecting link rotably fastened to said member at one end and rotatably fastened to said compression piston on the other end, and a second connecting link rotably mounted to said member at 180* from the fastening of said first connecting link and the other end rotably fastened to said cushion piston.
 3. The apparatus of claim 1 wherein said rotably mounted member is wheel-shaped and said connecting links are fastened at the rim thereof.
 4. The apparatus of claim 1 wherein said fluid is lubricating oil and said refrigerant is Freon.
 5. The apparatus of claim 1 wherein said evaporator means is in communication with the backside of the larger end of said compression piston and said cushion piston thereby applying the evaporator pressure to said backsides and said condenser means is in communication with the forward side of the larger end of said cushion piston thereby applying the condenser pressure to said forward side.
 6. In a process for cooling contained exterior atmosphere by compression, condensation, expansion, evaporation cooling cycle, the improvement comprising; the steps of compressing contained gaseous refrigerant by a reciprocating compression piston driven by an incompressible fluid in communication with the pressure sensitive means of a heat engine having alternate cycles of higher and lower pressure conditions, said compression piston being in interconnecting mechanical linkage with an opposing cushion piston so that the pistons move oppositely to provide dynamic and pressure force balance, and damp the dynamic instabilities of the system.
 7. The process of claim 6 wherein the evaporator is in communication with the backside of each said compression and said cushion pistons applying evaporator pressure to said backsides and the condenser is in communication with the forward side of said cushion piston applying condenser pressure to said forward side.
 8. The process of claim 6 wherein said fluid is lubricating oil and said refrigerant is Freon. 